The present invention relates to a fluid dispenser pump, and more particularly to a novel implementation of the actuating rod of the pump.
A fluid dispenser pump conventionally comprises a pump body in which a piston connected to an actuating rod is slidably mounted in leaktight manner. The actuating, rod is mounted to slide inside an element that is generally fixed to the top edge of the pump body, and that may be a ferrule, a xe2x80x9cturretxe2x80x9d, or the like. Depending on the type of pump, the interface between the actuating rod and the inside surface of the ferrule (or of the element used as the ferrule) can be leaktight or otherwise. In particular, in fluid dispensers, which are either airless, or else have a venting hole located at a specific place, e.g. so as to put a suitable bacteria filter in it, the actuating rod is preferably mounted to slide in leaktight manner inside the ferrule. However, between two elements that are generally made of a relatively hard plastics material, leaktightness is not easy to obtain, and it is sometimes necessary to make provision for there to be a considerable amount of friction between the two elements in order to guarantee a certain level of leaktightness. In addition, with that type of pump, e.g. when it is designed to be used as a nasal dispenser, it can happen that the user does not exert a force that is exactly axial on the actuating rod, which either prevents the pump from being actuated or else degrades the leaktightness between the actuating rod and the ferrule.
An object of the present invention is to provide a fluid dispenser pump that does not reproduce the above-mentioned drawbacks.
In particular, an object of the present invention is to provide a fluid dispenser pump that guarantees excellent leaktightness between the actuating rod and the ferrule, or any other similar element co-operating with the actuating rod.
In addition, an object of the present invention is to provide a fluid dispenser pump that is simple and inexpensive to manufacture and to assemble.
Another object of the present invention is to provide a fluid dispenser pump that makes it possible for the pump to be actuated even when the user exerts a force that is not exactly axial on the actuating rod. In which case, it can be said that the pump procures a xe2x80x9cball-coupling effect.xe2x80x9d More particularly, an object of the present invention is to provide such a pump having a ball-coupling effect that also guarantees leaktightness between the actuating rod and the ferrule.
The invention therefore provides a fluid dispenser pump comprising a pump body in which a piston connected to an actuating rod is slidably mounted in leaktight manner, said actuating rod being mounted to slide inside an element, such as a ferrule, which is secured to the pump body, said fluid dispenser pump being characterized in that said actuating rod includes a flexible outer tubular portion that is in leaktight contact with said element, and a rigid inner tubular portion that is concentric with said flexible outer tubular portion, the zone of contact between the inside of the ferrule and the actuating rod being leaktight regardless of the position of said actuating rod.
In a first embodiment of the invention, the flexible outer tubular portion has a first axial end that is free, and a second axial end that is secured to or integral with said actuating rod and in particular integral therewith.
In a second embodiment of the invention, both of the axial ends of the flexible outer tubular portion are secured to or integral with the actuating rod and in particular integral therewith.
Advantageously, a metering chamber is defined between an inlet valve and an outlet valve, the space between the outer tubular portion and the inner tubular portion of the actuating rod being part of said metering chamber.
The present invention also provides a fluid dispenser device including a pump as defined above.